Movable Color Sensor for Image Reading Apparatus
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Solution Overview
Problem
Existing image forming systems require multiple color sensors in a row to read patch images and determine uniformity, increasing costs and risking sheet jamming due to interference with guide members when trying to move sensors in the main scanning direction.
Innovation Solution
An image reading apparatus with a movable color sensor that reads image information by moving in the sheet's width direction, using a conveyance system with retractable guide shutters to prevent sheet jamming and reduce the need for multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed color sensor is used to read patch images, then only patch images aligned at a corresponding position in the main scanning direction can be read, but arranging multiple color sensors in a row increases system cost
Solution Approach 1:
The color sensor is made movable in the main scanning direction through a conveyance mechanism. The sensor can be positioned at different locations along the main scanning direction to read patch images at various positions, replacing the need for multiple fixed sensors and reducing system cost while maintaining comprehensive measurement capability
Solution Approach 2:
A guide member is introduced as an intermediary component to define the sheet conveyance path and enable precise positioning of the movable color sensor. The guide member facilitates the sensor's movement along the main scanning direction while maintaining accurate alignment with patch images, solving the positioning problem without requiring multiple sensors
2Measurement precision
If the color sensor is moved in the main scanning direction to read multiple patch images, then reading capability is improved, but the guide member that defines sheet conveyance path interferes with the color sensor
Solution Approach 1:
The conveyance system is segmented into distinct functional zones: the guide member defines the sheet conveyance path in the sub-scanning direction, while the color sensor moves independently in the main scanning direction. This spatial segmentation allows both components to coexist and function without interference, with the guide member remaining stationary and the sensor moving freely along its axis
Solution Approach 2:
The color sensor's movement is transitioned from the sub-scanning direction (where guide member interference would occur) to the main scanning direction. By changing the dimension of movement, the sensor can read multiple patch images across the sheet width without conflicting with the guide member that constrains sheet movement in the sub-scanning direction
3Ease of operation
If guide members are present to define sheet conveyance path, then sheet conveyance is controlled, but the possibility of sheet jamming is increased when color sensor moves in main scanning direction
Solution Approach 1:
The guide member is designed with dynamic positioning capability, allowing it to move between a conveyance position (where it defines the sheet path) and a retracted position (where it clears the main scanning direction). This dynamic adjustment reduces sheet jamming risk during color sensor movement while maintaining conveyance control when needed
Solution Approach 2:
The guide member is retracted in advance before the color sensor moves in the main scanning direction, and returned to the conveyance position after reading is complete. This preliminary action prevents potential sheet jamming during sensor movement while ensuring proper sheet conveyance control during normal operation
Data Source
AI summary
An image reading apparatus includes a first conveyance roller, a second conveyance roller, a first conveyance guide, a second conveyance guide configured to move between an opposed position being opposed to the first conveyance guide and a retracting position being retracted from the opposed position, and an image reading unit opposed to the first conveyance guide and configured to move in a width direction orthogonal to the sheet conveyance direction and read image information on a sheet. The second conveyance guide is configured to move to the retracting position in response to the image reading unit moving in the width direction and reading the image information on the sheet.